In certain fields, such as in the laboratory and research fields, it is often necessary to purchase and use chemicals that are extremely expensive which may also be highly corrosive and/or toxic. Typically, such chemicals are purchased in plastic bottles having a typical threaded closure system. With such chemicals, it is important to avoid or minimize the amount of leakage of liquid and/or vapor from the bottle, particularly during shipment and storage. In order to provide a better seal in the bottle, the prior art has typically placed a sealing gasket within the closure which mates with the top of the rim of the neck portion on which it is placed. While such gaskets do improve sealing to a certain extent, it does not work effectively in certain situations. For example, during shipping and storage of liquid filled bottles, the temperature of the liquid within the bottle can increase such that the pressure therein causes the closure to deform allowing vapors and/or liquid to escape over time. It has also been suggested in the prior art the use of a rigid plug which fits within the neck portion of the container and has a sealing lip located between the top of the rim and the closure. This plug functions much as a gasket or washer would. However, this structure has not been effective in reducing the escape of vapors and/or liquid to acceptable levels. Such prior art closure assemblies rely mainly on the seal between the top of the rim and the cap. As such, cannot compensate effectively in response to temperature changes and still maintain an effective sealing engagement between the closure and neck portion of the bottle.
There has also been suggested in the prior art the use of a cap wherein a sealing rib engages a beveled portion on the inside surface of the rim of a bottle. While this does provide improved sealing capabilities between the closure and bottle, this arrangement still does not provide adequate sealing to prevent vapors and/or liquids from escaping under extreme environmental conditions.
Applicant has invented a bottle closure assembly which provides a high degree of sealing which minimizes or prevents the escape of small amounts of vapor and/or liquid from the bottle during extreme environmental changes that may be experienced.